#31834: Cannot sqlmigrate on Django migrations that change unique_together
-------------------------------------+-------------------------------------
Reporter: Brіаn Lаі | Owner: nobody
Type: Bug | Status: new
Component: Database layer | Version: 3.0
(models, ORM) |
Severity: Normal | Resolution:
Keywords: sqlmigrate | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Description changed by Brіаn Lаі:
Old description:
> Somewhat similar to #26624, but forward sqlmigrate, reproduced on Django
> 3.0.8 and Postgres 10.x.
>
> If a model has a unique_together of
>
> {{{
> unique_together = [
> (a, b)
> ]
> }}}
>
> and it becomes
>
> {{{
> unique_together = [
> (a, b, c)
> ]
> }}}
>
> , although the makemigrations command successfully generates a new
> migration with the corresponding AlterUniqueTogether() operation, the
> migration cannot be inspected with the sqlmigrate command.
>
> Reproduce bug with the following (the project may also be attached)
>
> {{{
> class Model1(models.Model):
> id = models.IntegerField(primary_key=True)
> name = models.CharField(max_length=255, unique=True)
>
> class Model2(models.Model):
> id = models.IntegerField(primary_key=True)
> link_id = models.CharField(max_length=255)
> settings = models.ForeignKey(Model1, on_delete=models.CASCADE)
>
> class Model3(models.Model):
> id = models.IntegerField(primary_key=True)
> order = models.IntegerField()
> model_2 = models.ForeignKey(Model2, on_delete=models.CASCADE)
> direct = models.BooleanField(default=True)
>
> class Meta:
> unique_together = [
> ('model_2', 'order')
> # To get the bug, change this to ('model_2', 'order',
> 'direct') and sqlmigrate the migration that this creates.
> ]
> }}}
New description:
Somewhat similar to #26624, but forward sqlmigrate, reproduced on Django
3.0.8 and Postgres 10.x.
If a model has a unique_together of
{{{
unique_together = [
(a, b)
]
}}}
and it becomes
{{{
unique_together = [
(a, b, c)
]
}}}
, although the makemigrations command successfully generates a new
migration with the corresponding AlterUniqueTogether() operation, the
migration cannot be inspected with the sqlmigrate command.
Reproduce bug with the following (the project may also be attached)
{{{
class Model1(models.Model):
id = models.IntegerField(primary_key=True)
name = models.CharField(max_length=255, unique=True)
class Model2(models.Model):
id = models.IntegerField(primary_key=True)
link_id = models.CharField(max_length=255)
settings = models.ForeignKey(Model1, on_delete=models.CASCADE)
class Model3(models.Model):
id = models.IntegerField(primary_key=True)
order = models.IntegerField()
model_2 = models.ForeignKey(Model2, on_delete=models.CASCADE)
direct = models.BooleanField(default=True)
class Meta:
unique_together = [
('model_2', 'order')
# To get the bug, change this to ('model_2', 'order',
'direct') and sqlmigrate the migration that this creates.
]
}}}
The error shown in the terminal is:
{{{
Traceback (most recent call last):
File "manage.py", line 22, in <module>
execute_from_command_line(sys.argv)
File "/lib/python3.6/site-packages/django/core/management/__init__.py",
line 401, in execute_from_command_line
utility.execute()
File "/lib/python3.6/site-packages/django/core/management/__init__.py",
line 395, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/lib/python3.6/site-packages/django/core/management/base.py", line
328, in run_from_argv
self.execute(*args, **cmd_options)
File "/lib/python3.6/site-
packages/django/core/management/commands/sqlmigrate.py", line 30, in
execute
return super().execute(*args, **options)
File "/lib/python3.6/site-packages/django/core/management/base.py", line
369, in execute
output = self.handle(*args, **options)
File "/lib/python3.6/site-
packages/django/core/management/commands/sqlmigrate.py", line 65, in
handle
sql_statements = executor.collect_sql(plan)
File "/lib/python3.6/site-packages/django/db/migrations/executor.py",
line 225, in collect_sql
state = migration.apply(state, schema_editor, collect_sql=True)
File "/lib/python3.6/site-packages/django/db/migrations/migration.py",
line 124, in apply
operation.database_forwards(self.app_label, schema_editor, old_state,
project_state)
File "/lib/python3.6/site-
packages/django/db/migrations/operations/models.py", line 525, in
database_forwards
getattr(new_model._meta, self.option_name, set()),
File "/lib/python3.6/site-packages/django/db/backends/base/schema.py",
line 380, in alter_unique_together
self._delete_composed_index(model, fields, {'unique': True},
self.sql_delete_unique)
File "/lib/python3.6/site-packages/django/db/backends/base/schema.py",
line 414, in _delete_composed_index
", ".join(columns),
ValueError: Found wrong number (0) of constraints for bar_model3(model_2,
order)
}}}
--
--
Ticket URL: <https://code.djangoproject.com/ticket/31834#comment:2>
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